1. Field of the Invention
The present invention relates to a multilayer substrate and an electronic device and particularly relates to a multilayer substrate including, for example, a coil antenna and a magnetic member and component and an electronic device including the multilayer substrate.
2. Description of the Related Art
Conventionally, a surface mount coil antenna included in a HF band communication system has been devised.
For example, WO 2014/024762 discloses a surface mount antenna device including a multilayer substrate, a coil antenna, a first ground conductor and a second ground conductor, and an interlayer connection conductor. A plurality of dielectric sheets is laminated in the multilayer substrate. The coil antenna includes a winding axis orthogonal or substantially orthogonal to a lamination direction of the multilayer substrate. The first ground conductor and second ground conductor are located on the outer side of a coil conductor. The interlayer connection conductor electrically connects the first ground conductor and the second ground conductor to each other. A surface mount antenna device is mounted on a wiring substrate (printed wiring substrate), and a winding axis of the coil antenna is parallel or substantially parallel to a main surface of the wiring substrate.
However, in the case where the antenna device described in WO 2014/024762 is mounted on the main surface of a wiring substrate or the like, if another electronic component or structure is located adjacent to or in vicinity of the antenna device, magnetic flux interlinking the coil antenna is disturbed, and the magnetic flux interlinking with the coil antenna of a communication partner is reduced. For this reason, not to reduce the magnetic flux interlinking with the coil antenna of the communication partner, it is necessary to mount the antenna device at a position around which no other electronic components or structures are located. Therefore, the degree of freedom in arrangement of the antenna device is low.
In addition, since a metal member, for example, a conductor pattern or a ground conductor, is usually in contact with a wiring substrate or the like, when the antenna device described in WO 2014/024762 is mounted on the main surface of the wiring substrate or the like, the metal member and the coil antenna may be unnecessarily coupled with each other. Therefore, a coupling coefficient with the antenna of the communication partner decreases, and as a result, communication characteristics of the coil antenna may be degraded.